In recent years, wind turbine generators using wind power are attracting attention as apparatuses for generating power using clean energy (for example, refer to Patent Document 1).
As an example of the above-described wind turbine generators, a wind turbine generator including a plurality of wind-turbine rotor blades rotated by wind power and a rotor head to which the wind-turbine rotor blades are attached is known.
The wind-turbine rotor blades include fixed-pitch-type wind-turbine rotor blades that are fixed to the rotor head and have a fixed pitch and variable-pitch-type wind-turbine rotor blades whose pitch is varied according to the wind speed. The type is selected according to the conditions of use.
Variable-pitch-type wind-turbine rotor blades typically have gaps between a head capsule for covering the rotor head and the wind-turbine rotor blades to change the pitch.
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2007-32420